Troubleshooting Tip: FortiGate 40F 3G/4G WWAN registers the SIM card with error 'Modem activation fails!'

[bstefanovski]

Description	This article describes the troubleshooting steps for a FortiGate 40F 3G/4G WWAN interface that fails to obtain an IP address. The FortiGate is able to detect the SIM card, but throws the error 'Modem activation fails!'.
Scope	FortiGate.
Solution	Run the command below where it will shows whether the 3G/4G SIM card can be detected. diagnose sys lte-modem sim-info Active Slot: Slot 1. SIM state: QMI_UIM_CARD_STATE_PRESENT   <----- Detected Next its a debug to be collected as below: diagnose debug application lted -1 diagnose debug enable sierra_qmi_wwan_get_sim_slot(864)-201: Current active slot: slot 1! UIM State ==> QMI_UIM_CARD_STATE_PRESENT  <----- The SIM card is detected. _usb_qmi_wwan_active_modem(702)-231: Modem PS state is QMI_NAS_ATTACH_STATE_DETACHED, do not dial!  <----- update_modem_status(584)-231: Packet Service Detached! No Connection with e-NodeB. Check signal reception update_modem_status(589)-231: modem_offline_time: 3813 Current Jiffies: 32618 update_modem_status(666)-231: Modem activation fails! <----- The error. If the errors appear in the debug logs, open a ticket with TAC support.